extjs - Enable button only when multiple textfields have value

Question

So I have multiple Panel which have textfields in them. How can I add a listener to check if the value has been entered in the multiple textfields and enable the button or if no value, keep it disabled.

The button is in a different Panel, all the textfields are in different Panel.

I am aware of using formbind, but that only works when you are working with form type. Edit:

It's Extjs4

An idea of what the code looks like

Answer 1

等待大神答复